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Message-ID: <66f7b3a0.050a0220.46d20.0038.GAE@google.com>
Date: Sat, 28 Sep 2024 00:43:28 -0700
From: syzbot <syzbot+288aa6838b3263f52e7e@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, hughd@...gle.com, linux-kernel@...r.kernel.org,
linux-mm@...ck.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mm?] possible deadlock in shmem_file_write_iter
Hello,
syzbot found the following issue on:
HEAD commit: e477dba5442c Merge tag 'for-6.12/dm-changes' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=102ade27980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b2d4fdf18a83ec0b
dashboard link: https://syzkaller.appspot.com/bug?extid=288aa6838b3263f52e7e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/be1e82b0133d/disk-e477dba5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8d9e4b1a6733/vmlinux-e477dba5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b79025eddfb1/bzImage-e477dba5.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+288aa6838b3263f52e7e@...kaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-11624-ge477dba5442c #0 Not tainted
------------------------------------------------------
syz.2.1702/9983 is trying to acquire lock:
ffff888028091e18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
but task is already holding lock:
ffff888077ef3708 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
ffff888077ef3708 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: shmem_file_write_iter+0x80/0x120 mm/shmem.c:3211
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
down_write+0x99/0x220 kernel/locking/rwsem.c:1579
inode_lock include/linux/fs.h:815 [inline]
process_measurement+0x439/0x1fb0 security/integrity/ima/ima_main.c:250
ima_file_mmap+0x13d/0x2b0 security/integrity/ima/ima_main.c:455
security_mmap_file+0x7e7/0xa40 security/security.c:2977
__do_sys_remap_file_pages mm/mmap.c:1692 [inline]
__se_sys_remap_file_pages+0x6e6/0xa50 mm/mmap.c:1624
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&mm->mmap_lock){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3158 [inline]
check_prevs_add kernel/locking/lockdep.c:3277 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
__lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
down_read_killable+0xca/0xd30 kernel/locking/rwsem.c:1549
mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
get_mmap_lock_carefully mm/memory.c:6108 [inline]
lock_mm_and_find_vma+0x29c/0x2f0 mm/memory.c:6159
do_user_addr_fault arch/x86/mm/fault.c:1361 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
fault_in_readable+0x165/0x2b0
fault_in_iov_iter_readable+0x229/0x280 lib/iov_iter.c:94
generic_perform_write+0x259/0x6d0 mm/filemap.c:4040
shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3221
new_sync_write fs/read_write.c:590 [inline]
vfs_write+0xa6f/0xc90 fs/read_write.c:683
ksys_write+0x183/0x2b0 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&sb->s_type->i_mutex_key#12);
lock(&mm->mmap_lock);
lock(&sb->s_type->i_mutex_key#12);
rlock(&mm->mmap_lock);
*** DEADLOCK ***
3 locks held by syz.2.1702/9983:
#0: ffff888054784478 (&f->f_pos_lock){+.+.}-{3:3}, at: fdget_pos+0x24e/0x320 fs/file.c:1187
#1: ffff88814a584420 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2931 [inline]
#1: ffff88814a584420 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x224/0xc90 fs/read_write.c:679
#2: ffff888077ef3708 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:815 [inline]
#2: ffff888077ef3708 (&sb->s_type->i_mutex_key#12){+.+.}-{3:3}, at: shmem_file_write_iter+0x80/0x120 mm/shmem.c:3211
stack backtrace:
CPU: 1 UID: 0 PID: 9983 Comm: syz.2.1702 Not tainted 6.11.0-syzkaller-11624-ge477dba5442c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
check_prev_add kernel/locking/lockdep.c:3158 [inline]
check_prevs_add kernel/locking/lockdep.c:3277 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
__lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
down_read_killable+0xca/0xd30 kernel/locking/rwsem.c:1549
mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:153
get_mmap_lock_carefully mm/memory.c:6108 [inline]
lock_mm_and_find_vma+0x29c/0x2f0 mm/memory.c:6159
do_user_addr_fault arch/x86/mm/fault.c:1361 [inline]
handle_page_fault arch/x86/mm/fault.c:1481 [inline]
exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:fault_in_readable+0x165/0x2b0 mm/gup.c:2235
Code: b3 ff 4c 8d b3 ff 0f 00 00 48 89 d8 4d 01 e6 49 81 e6 00 f0 ff ff 49 39 c6 72 6b e8 f5 c8 b3 ff 4c 39 f3 74 6e 4c 89 64 24 10 <44> 8a 23 43 0f b6 04 2f 84 c0 75 18 44 88 64 24 40 48 81 c3 00 10
RSP: 0018:ffffc900045c7a40 EFLAGS: 00050283
RAX: ffffffff81e0eba7 RBX: 00000000201e1000 RCX: 0000000000040000
RDX: ffffc9001ddf8000 RSI: 000000000000bffd RDI: 000000000000bffe
RBP: ffffc900045c7af8 R08: ffffffff81e0eb18 R09: ffffffff84b912a9
R10: 0000000000000002 R11: ffff888025213c00 R12: 0000000000200000
R13: dffffc0000000000 R14: 0000000020201000 R15: 1ffff920008b8f50
fault_in_iov_iter_readable+0x229/0x280 lib/iov_iter.c:94
generic_perform_write+0x259/0x6d0 mm/filemap.c:4040
shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3221
new_sync_write fs/read_write.c:590 [inline]
vfs_write+0xa6f/0xc90 fs/read_write.c:683
ksys_write+0x183/0x2b0 fs/read_write.c:736
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbca257df39
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbca3459038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fbca2735f80 RCX: 00007fbca257df39
RDX: 000000000208e24b RSI: 0000000020000100 RDI: 0000000000000003
RBP: 00007fbca25f0216 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fbca2735f80 R15: 00007ffd5bf037c8
</TASK>
----------------
Code disassembly (best guess):
0: b3 ff mov $0xff,%bl
2: 4c 8d b3 ff 0f 00 00 lea 0xfff(%rbx),%r14
9: 48 89 d8 mov %rbx,%rax
c: 4d 01 e6 add %r12,%r14
f: 49 81 e6 00 f0 ff ff and $0xfffffffffffff000,%r14
16: 49 39 c6 cmp %rax,%r14
19: 72 6b jb 0x86
1b: e8 f5 c8 b3 ff call 0xffb3c915
20: 4c 39 f3 cmp %r14,%rbx
23: 74 6e je 0x93
25: 4c 89 64 24 10 mov %r12,0x10(%rsp)
* 2a: 44 8a 23 mov (%rbx),%r12b <-- trapping instruction
2d: 43 0f b6 04 2f movzbl (%r15,%r13,1),%eax
32: 84 c0 test %al,%al
34: 75 18 jne 0x4e
36: 44 88 64 24 40 mov %r12b,0x40(%rsp)
3b: 48 rex.W
3c: 81 .byte 0x81
3d: c3 ret
3e: 00 10 add %dl,(%rax)
---
This report is generated by a bot. It may contain errors.
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